Transmitting device



- 1931! c. c. MURDICK TRANSMITTING DEVICE Filed Dec. 24, .1928

gwua'nlfoz 6770/166 6. Ward/ck WMQWM Patented Dec. 8, 1931 UNITEPQSTATES rATENro-FFic onimiins cinnamon, or troiinno, OHIO "'rnaivsiviircr ne DEVICE r This invention relates to the art of transmitting and reproducing sound, and more particularly to a method orimeans forcha igiiig sound impressions orvlbrations into electrical impulses. The invention has-for an object the provision of al'system including a magnetizable element connected to a sound responsive member, the parts beingfso a1 ranged that the element is adaptedfto'vibrate in unison with the member,- the'system having ineans forincreasing the amplitude of the electrical impulses iset up by'the 'vibrations of theso'uii'd responsive-element.

The invention further jcomprehends-"the use of an electrically" energized element adapted to'set up a inagnetic'fiux adjacent the vibratory elements associated with means for transforming the sound vibrations 'into electrical impulses;

The invention further embraces asystem of sound reproducing elements wherein certain parts arev renderedndjiistable so that modulation of the electrical impressions resulting from sound vibrations can bea plilied or reduced in the electrical transmittingsystem. i

Further objects and advantages are within the scope of this invention such as relate to the arrangement, operation and function so of the related elements of the structure, to various details of construction and to combinations of parts, elements per se, and to economies of manufacture and numerous other features as will be apparent from a -consideration of the specification and draw Referring to the drawings, I have shown the device of my invention asassociated with a transmitting circuit of the usual type,but

to asource of power G.

itis to beunderstood that I' contemplate the use of'n y inventi n'in any circuit or "place hwhere the same 'iiiay befouiid applicable. In Figure 1 I have shown diagrammatically the transmitter 10tor changing sound vibrations into electrical impulses, connected by means of a modulating transformer 12 to a transmitting circuit, the one illustrated coin- "prising' a modulating'tube 13 together with an oscillating tube llsuitably conn-ectedin cuit is supplemented with necessary acres sories such as, 'for example, condensersfl'n and 18, frequency choke coil 19 and a current stabilizer or choke coil 20 which is connected Referring particularly to Figure 2, I have shown a'fo'rm of my device as comprisinga ,base 24'support1ng a member 25 having a mouthpiece 26, tlie member 25 carrying a diaphragm or disc 27' adapted to vibrate or oscillate under the influence of sound impressions. Fixedsubstantially to the center of the diaphragm 27, preferably welded or otherwise secured, is a magnetizable iron bar or 'core 29 which projects rearwardly from the diaphragm and supports anenergizing coil 30, which as shown in Figure 1, may be connected to a battery 31 or other suitable source of electrical energy. The extremity of the corev 29 preferably projects into an v opening in a second coil -34, in which currents are setup "due tothe vibratory movements of- :the core 29 moving in synchronism with the vibrations of the diaphragm 2'7. This coil 34, as shown in Figure 1, is preferablyconnected' through the modulatingtransformer 12 to the circuit for electrically transmitting the sound impressions. The coil 3lis preferably inounted upon a base member- 35 adjusltably supported iipona bracket 36,the

latter carriedby the base 24;, the member 35 being secured to the bracket 36 by means of ascrew 37 and a wing nut 38 so as to render the coil 34 adjustable with respect to the core 29 for varying theiiitensityof the magnetic flux 7 acting on coil 3% an oscillating circuit 15, the electrical im- "pulsesbeing transmitted tlirough an oscillat- 'lllgtransformer 16, connected to" suitable groundand antenna connections; The cir- In the operation of this form of the device, the sound impressions react upon the diaphragm 27 causing the latter together with the iron core 29 and energizing coil 30 to vibrate, these movements of the core and energizing coil act to set up currents in the coil 34 due to the alternate fluctuations of the magnetic flux adjacent the coil 34. The energizing coil and core member 29 are con structed as light in weight as possible so that these parts do not materially damp the magnitude of the vibrations of the diaphragm 27.

In the form of my invention shown in Figure 3, the base 38 carries a diaphragm supporting element 39 and a mouthpiece 40, a diaphragm 41 being secured to the element 89. Fixed to the center of the diaphragm by suitable means is a U-shaped magnet 44 which is separated from the diaphragm by means of a collar 45. The diaphragm 41 may be made of sheet metal, paper or other fibrous material; however, it may be desirable, if the construction be of metal, to separate the magnet therefrom by constructing the collar 45 of non-magnetic material so that the diaphragm will form no direct part of the magnetic circuit existing adjacent to the magnet 44. The furcations 47 and 48 of the magnet 44 project into openings in the center of two similar coils 49 and 50, these coils being connected together and subsequently connected to the modulation transformer by means of the leads 51. The purpose of utilizing two similar coils surrounding the furcations of the magnet is to increase or" amplify the amount of current set up in the coils 49 and 50. These coils are mounted upon a base plate 53 supported upon a bracket 54 and adjustably secured thereto, the adjustment being bad by manipulation of the wing nut 55.

In the operation of this form of device, the vibratory movements of the diaphragm 41 obviously are imparted to the magnet 44 causing the furcations thereof, 47 and 48, to move longitudinally of the coils 49 and thus setting up currents therein which may be conveyed to the transmitting mechanism.

In the modification shown in Figure 4, a U-shaped member 60, preferably constructed of nonmagnetic material, is fixedly secured to the diaphragm 61, the member carrying a coil 62. Fixed to an adjustable bracket 64 a cylindrical magnetizable core member 65 which projects into the coil carrying element 60 and is surrounded by an energizing coil 66 which may be connected to a suitable source of power through the leads 67. In this form of device the iron core 65 is energized by current passing through coil 66thus setting up a highly magnetized field adja cent the coil 62, vibrations of the diaphragm 61 ope ating to move the coil 62 relative to the core member 65 so that currents are set up in the coil 62 which may be communicated to the transmitting system.

It is apparent that, within the scope of the invention modifications and different arrangements may be made other than is herein disclosed, and the present disclosure is illustrative merely, the invention comprehending all variations thereof.

What I claim is:

1. In a device of the character disclosed, in combination, a supporting member; a vibratory diaphragm carried by said supporting member; a magnetizable core secured to said diaphragm; energizing means for said core carried thereby; a coil in close proximity with the core element, the parts being so arranged that vibratory movements of said core induce electrical impulses in said coil.

2. In a device of the character disclosed, in combination, a sound responsive element; a magnetizable core secured to said sound responsive element; energizing means carried by said core; a coil juxtaposed with respect to said core member, said coil being rendered adjustable with respect to said core for varying the relative normal positions of said core element and said coil.

3. In a device of the character disclosed, in combination, a supporting member; a metallic diaphragm carried thereby; a magnetizable core element fixedly secured to said diaphragm;a coil carried by said core element; a source of power for said coil; a second coil juxtaposed with respect to said core member and adjustable relative thereto, the parts being so arranged thatmoveme-nts of said core member act to set up electrical impulses in said second coil.

4. In a device of the character disclosed, in combination, a vibratory diaphragm; a U-shaped magnetizable member secured to said diaphragm; a plurality of coils cooperating with said Ushaped member, the. parts being so arranged that movements of said diaphragm and magnetizable clement induce electrical impulses in said coils.

In testimony whereof, I aflix my signature.

CHARLES C. MURDICK. 

